Gas compressor



'Milly 2 0, 1930.- A. HOERBIGER 1,759,617

GAS COMPRESSOR Filed Aug. 2v, 1928 Patented May 20, 1930 UNITED STATES PATENT oFFlcE.,

ALFRED I-IOERBIGER, OIE MAUER, NEAR VIENNA, AUSTRIA, ASSIGNOR TO THE FIRM HOERBIGER & CO., OF MAUER, NEAR VIENNA, AUSTRIA GAS COMPRESSOR 4Application led August 27, 1928, Serial No. 302,324, and in Austria August 27, 1927.

My invention relates togas compressors of that class in which the air is compressed.

in a plurality of successive steps that is to say to multi-step gas compressors.

5 My invention consists in that the reservoirs associated to any two successive compression steps are connected by a control element acted upon by the pressures existing in both reservoirs and adapted to maintain a substanl tially constant ratio between the pressures in is liable to become excessive. This may happen for instance if a two step compressor is used for a locomotive operated by a Diesel motor and the reservoir associated to the rst step has to supply air under pressure .for operating the brakes while the reservoir associate'd to the second or high pressure step has to supply the air under pressure for starting. The frequent supply of air under pressure for operating the brakes may then result in an exhaustion of the corresponding reservoir. y

The drawing shows` diagrammatically, a vertical section view through a constructional form of a two stage compressonconstructed in accordance with the present invention.

Referring to the drawing it w1ll be noted 40 that the compressor has a differential piston comprising a lower piston 1 and an upper piston 6 concentrically mounted with and upon the lower piston and of less diameter than it. The vlower piston operates in a cylinder 1a and serves to compress atmospheric air delivered lto that' cylinder throughan intake valve 2. The compressed air is d ischarged through a delivery valve 3 and pipe line 3a, to a reservoir 4, from which the compressed air may be withdrawn through exit 5 in acylinder 6a.

shown.

` The upper high pressure piston 6, operates s This cylinder 6il has air under pressure supplied to it from reservoir 4 through a pipe line 7 connecting the reservoir and cylinder. A high pressure intake valve 7a is located in intake pipe 7 and a high pressure delivery valve 8a is located in a deliverypipe 8. This delivery pipe connects the high pressure cylinder 6a and a high pressure reservoir comprising two intercom' nected chambers 10, 1l communicating with each other through an automatic. valve 9.

H the pressure in the chamber 11, communicating with a consumption device not shown through a pipe 12, is reduced, air under pressure flows from the chamber 10 into the chamber 11 through the automatic valve 9. Therefore the pressures existing in the chamber l0 and the chamber 1l are always sub- ,by a duct containing valve 13 having a dierential piston geometrically similar to the pump piston hereinbefore described. This valve piston operates in a cylinder 14 and comprises a lower reduced stem 14c and an upper enlarged head 14b in communication with the reservoir 4 through pipe 5a. The stem 14c seats upon port 13a in the communieating duct between reservoirs 10 and 4 to prevent passage of high pressure air from reservoir 10 to reservoir 4 except when the pressure in the' reservoir 10 is so much greater than the pressure in reservoir 4 that port V13a will be opened by the excess pressure on the stem 14, thus allowing high pressure air to enter reservoir 4.

To assist the valve in maintaining the port l 13n closed, a coil spring l5 is located within lthe cylinder 14a and presses on the head 141.

i the valve 13 will be in equilibrium, but when v the pressure in the reservoir 4 drops the valve 13 will open admitting air from chamber v1'0.

Each stroke of the piston 6 takes air from reservoir 4 and tends to increase the pressure in chamber 10 by a certain amount, and if the pressure at which the air is 'delivered to piston 6 is high then the pressure at which the air is delivered to the chamber 10 will be that high plus the amount of compression it has` been subjected to under piston 6. Thusfon account of the fact that the air in chambers 10l and 12 comes from reservoir 4 the ratio of 1. In a multistage gas compressor, the

' combination of at least two compressing cy 1 stant ratio inders and pistons working therein, a reservoir for each of ,said cylinders communicating with the delivery sides of said cylinders, a duct connecting the reservoirs of two successive compressor stages, and means adapted to maintain a substantially conbetween the pressures in the said reservoirs, said means being included in said duct and being responsive to the pressures 1n the two reservoirs which it connects.

. 2. In a multistage gas compressor, the combination of at least two compressing cylinders and pistons working therein, a reservoir for each of said cylinders communicating with the delivery sides of said cylinders, a duct connecting the reservoirs of two successive compressor stages, and means adapted to maintain a substantially constant ratio between the pressures in the said reservoirs, said means being included in said duct and being responsive to the pressures inthe two reservoirs which it connects, and a delivery .chamber communicating with one of lsaid reservoirs.

3. lIn a multistage gas compressor, the combination of at least two compressing cylinders and pistons working therein, a reservoir for each of said cylinders and communieating with the delivery sides of said cylinders, a' duct connecting the reservoirs of two successive compressor stages and means adapted to maintain a substantially constant ratio between the pressures in the said reservoirs said means being included in said lduct and being responsive to the pressures in the two reservoirs which it connects, and a delivery chamber communicating with one of voir for each o said cylinders communicating with the delivery vsides of said cylinders, a duct connecting the reservoirs of two successive compressor stages, and means adapted to maintain a substantially constant ratio between the pressures-in the saidreservoirs, said means including a piston having opposite faces differing in area and acted upon by the pressures in said reservoirs.

5. In a multistage gas compressor, the combination of at least two compressing cylinders and pistons working therein, a reservoir for each of said cylinders communicating with the delivery sides of said cylinders, a duct connecting thel reservoirs of 'two successive compressor stages, and means adapted to maintain a substantially constant ratio between the pressures in the said reservoirs, said means comprising a piston having opposite faces differing in area and acted upon by the pressures in said reservoirs, the smaller face controlling the duct between said reservoirs.

V6. In a gas compressor having a plurality of reservoirs successively connected, each having a different pressure, means to maintain a predetermined ratio of pressures between said reservoirs said means comprising a duct connecting successive reservoirs and having a one way valve therein, said Vvalve being adapted to open when said ratio -increases due to an increase in pressure in the high pressure reservoir or a decrease in pressure in the low pressure reservoir.

In testimony whereof I have aiixed my signature. I

said reservoirs by a passage having an automatic valve therein.

4. In a lmultistage gas compressor,x the combination of at least two compressingI cylindersand pistons working therein, a reser- 

